Summary

The provided web content outlines eight distinct methods for Spring Boot to receive parameters from HTTP requests.

Abstract

The article on the undefined website presents a concise guide to handling HTTP request parameters in Spring Boot applications. It covers a range of techniques, from using formal parameters and entity classes to more complex structures like arrays, sets, and maps. The article also discusses the use of annotations such as @RequestParam, @PathVariable, and @RequestBody to facilitate parameter retrieval. Additionally, it touches on the direct use of HttpServletRequest and the handling of JSON format parameters through the @RequestBody annotation. Each method is illustrated with code examples, providing developers with a clear understanding of how to implement these parameter-receiving strategies in their Spring Boot controllers.

Opinions

The author suggests that formal parameters are best suited for scenarios with a limited number of parameters.
When dealing with entity parameters, the @RequestParam annotation should not be used with Get requests, as it is not supported for receiving parameters from entity classes.
Utilizing HttpServletRequest is presented as a flexible way to retrieve parameters without specifying their names in the method signature.
The @PathVariable annotation is recommended for extracting data from the URI path, which can be particularly useful for RESTful services.
For handling multiple values with the same parameter name, array parameters are a straightforward solution.
Set parameters are introduced as a way to handle an undefined number of parameters of the same type, providing a collection that excludes duplicates.
The @RequestBody annotation is highlighted as the preferred method for receiving JSON format parameters sent from the front end.
The use of a Map is suggested for receiving parameters either as query parameters using @RequestParam or as a JSON body using @RequestBody, offering a dynamic key-value pair structure.
The article concludes with a note of anticipation for future encounters, indicating the author's intention to continue sharing knowledge on the subject.

8 Ways Spring Boot Receives Parameters

This is a summary of how Spring Boot can receive parameters from HTTP requests.

How that will become one of your library stories.

1 . Formal Parameters

This approach is generally suitable for cases with fewer parameters.

@Slf4j
@RestController
@RequestMapping("/profile")
public class ProfileController {

    @GetMapping("/detail")
    public String getDetail(String uid) {
        log.info("uid:{}", uid);
       return "ok";
    }

}

if the parameter is labeled with @RequestParam, indicating that this parameter needs to be passed, otherwise an error will be reported.

@Slf4j
@RestController
@RequestMapping("/profile")
public class ProfileController {

    @GetMapping("/detail")
    public String getDetail(@RequestParam String uid) {
        log.info("uid:{}", uid);
       return "ok";
    }

}

2. Entity Parameters

@Slf4j
@RestController
@RequestMapping("/profile")
public class ProfileController {

    @GetMapping("/detail")
    public String getDetail(Profile profile) {
        log.info("profile:{}", profile);
       return "ok";
    }

}

The RequestParam annotation cannot be used when a Get request receives a parameter from an entity class, as it is not supported to get the parameter in this way.

3. Via HttpServletRequest

@RestController
@RequestMapping("/profile")
@Slf4j
public class ProfileController {

    @GetMapping("/detail")
    public String getDetail(HttpServletRequest request) {
        String name = request.getParameter("name");
        String sex = request.getParameter("sex");
        log.info("name:{}", name);
        log.info("sex:{}", sex);
       return "ok";
    }

}

4. Via the @PathVariable annotation

@RestController
@RequestMapping("/profile")
@Slf4j
public class ProfileController {

    @GetMapping("/detail/{name}/{sex}")
    public String getDetail(@PathVariable String name, @PathVariable String sex) {
        log.info("name:{}", name);
        log.info("sex:{}", sex);
       return "ok";
    }
}

5. Array Parameters

@RestController
@RequestMapping("/profile")
@Slf4j
public class ProfileController {

    @GetMapping("/detail")
    public String getDetail(String[] names) {
        Arrays.asList(names).forEach(name->{
            System.out.println(name);
        });
       return "ok";
    }

}

6. Set Parameters

@RestController
@RequestMapping("/profile")
@Slf4j
public class ProfileController {

    @GetMapping("/detail")
    public String getDetail(@RequestParam List<String> names) {
        names.forEach(name->{
            System.out.println(name);
        });
       return "ok";
    }

}

7. Via the @RequestBody annotation

The RequestBody annotation is used to receive json format parameters in the body passed from the frontend.

@RestController
@RequestMapping("/profile")
@Slf4j
public class ProfileController {

    @PostMapping("/save")
    public String getDetail(@RequestBody Profile profile) {
      log.info("name:{}", profile.getName());
      log.info("phone:{}", profile.getPhone());
       return "ok";
    }

}

8. Via Map

1. Pass the parameter as param, the RequestParam annotation receives the parameter.

@RestController
@RequestMapping("/profile")
@Slf4j
public class ProfileController {

    @PostMapping("/save")
    public String getDetail(@RequestParam Map<String,Object> map) {
        System.out.println(map);
        System.out.println(map.get("name"));
       return "ok";
    }

}

2. Pass the parameter in body JSON format and receive it in RequestBody annotation.

@RestController
@RequestMapping("/profile")
@Slf4j
public class ProfileController {

    @PostMapping("/save")
    public String getDetail(@RequestBody Map<String,Object> map) {
        System.out.println(map);
        System.out.println(map.get("name"));
       return "ok";
    }

}

See you next time! Thanks for reading.